Assessment of donor specific IgG Anti-HLA subclasses before and after kidney transplantation in Upper Egypt: A Single Center Study

Abstract

Donor specific antibodies (DSAs) are known as the leading cause of antibody mediated rejection (AMR), graft loss in kidney transplant (KT) recipients. DSAs characteristics, as immunoglobulin (Ig) classes, subclasses, and strength, are important to assess the immunological risk, early prediction of AMR, and therefor proper management. This longitudinal, case control study included 32 KT recipients at Assiut University Urology Hospital and 10 age and sex matched normal subjects as the control group. Total IgG, its subclasses and anti-human leukocyte antigen (anti-HLA) panel reactive antibody (PRA) were detected pre-transplantation (pre-TX), at 6-12- and 24-36-months post-TX. Rejection occurred in 4 recipients, 3 of them had high total IgG, IgG1 and/or IgG3. IgG2 and IgG4 were normal in all recipients. There were preformed anti-DSAs antibodies in 3/32 recipients (9.4%). Of these, two recipients became negative with no rejection occurred. The third recipient had high post-TX mean fluorescence intensity (MFI) and AMR occurred. The pre-TX PRA was negative in 29/32 recipients (90.6%). The PRA was negative in 8/29 recipients (27.6%) and the remaining 21/29 recipients (72.4%) developed de novo DSAs post-TX (MFI < 3000->10000). Rejection occurred with both low and high MFI. In 11 recipients, anti-HLA class I and II were not different between pre-TX, 3-6- and 24-36 months post-TX with no rejection occurred. The frequency and median levels of total IgG, IgG1 and IgG3 were increased in all recipients 24-36 months post-TX when compared with their levels pre-TX and 6-12 months post-TX in the 11 recipients and with the control group. The graft survival time significantly decreased in recipients with positive post-TX class I PRA. In conclusion, preformed DSAs may persist post-TX or turn negative. De novo DSAs developed post-TX even in non-sensitized recipients. Serum total IgG, IgG1 and IgG3 frequency increase 2-3 years post-TX.